Acute left heart failure and pulmonary edema usually have obvious differences, as follows: 1. The past history of patients is different. Patients with acute left heart failure usually have coronary heart disease, unstable angina or a past history of chronic heart failure, and are prone to acute left heart failure under certain factors, such as infection. 2. Patients with pulmonary edema usually have a history of chronic obstructive pulmonary disease, such as pneumonia, and will develop pulmonary edema.2. The clinical symptoms of patients also differ. The patient may be in a trance. Patients with pulmonary edema have obvious respiratory symptoms, such as dyspnea, coughing up large amounts of white foamy sputum, and inability to lie down.3 There are also obvious differences in the ancillary tests, as the BNP index is significantly elevated in patients with acute left heart failure, but in patients with pulmonary edema, the elevated index is usually not obvious.